Lens-fitted photo film unit, and method of making photo-print

Abstract

A lens-fitted photo film unit can take indoor- and night-photographs at adequate tone- and color-reproductions, by satisfying the condition:wherein T, A and S represents the shutter speed, the aperture size, and the ISO film speed. The film speed is determined to be not less than ISO640, and more preferably not less than ISO1000. The guide number (ISO100.m) of a flash device of the film unit is set to be in a range from 0.1 to 8, more preferably from 1 to 6, and most preferably from 3 to 5, and satisfies the condition: 8.0<=log2 (G2)+log2 (1/T)<=12.0, in combination with the shutter speed T.

What is claimed is:  
     
       1. A lens-fitted photo film unit containing a roll of unexposed filmstrip and having photographic mechanisms including a taking lens, a shutter mechanism and a stop, wherein the film unit can take photographs at a shutter speed T of the shutter mechanism and an aperture size A of the stop, the shutter speed T in the unit of second and the aperture size A satisfying the following condition: 
       
         
           −6≦2log 2 ( A )+log 2 (1/ T )−log 2 (0.3· S )≦5  
         
       
       wherein S represents an ISO film speed of the filmstrip.  
     
     
       2. A lens-fitted photo film unit as claimed in claim  1 , wherein the shutter speed T, the aperture size A and the ISO film speed S of the filmstrip satisfying the following condition: 
       
         
           −2≦2log 2 ( A )+log 2 (1/ T )−log 2 (0.3· S )≦4.  
         
       
     
     
       3. A lens-fitted photo film unit as claimed in claim  2 , wherein the shutter speed T, the aperture size A and the ISO film speed S of the filmstrip satisfying the following condition: 
       
         
           1≦2log 2 ( A )+log 2 (1/ T )−log 2 (0.3· S )≦3.  
         
       
     
     
       4. A lens-fitted photo film unit as claimed in claim  1 , wherein the ISO film speed of the filmstrip is not less than 640, and more preferably not less than 1000. 
     
     
       5. A lens-fitted photo film unit as claimed in claim  1 , further comprising a flash device for projecting a flashlight toward a photographic subject, wherein the flash device has a guide number (ISO100·m) in a range from 0.1 to 8, more preferably from 1 to 6, and most preferably from 3 to 5. 
     
     
       6. A lens-fitted photo film unit as claimed in claim  1 , further comprising a flash device for projecting a flashlight toward a photographic subject, wherein the film unit satisfies the following condition: 
       
         
           8.0≦log 2  ( G   2 )+log 2  (1/ T )≦12.0  
         
       
       wherein G represents a guide number (ISO100·m) of the flash device. 
     
     
       7. A lens-fitted photo film unit as claimed in claim  6 , wherein the guide number (ISO100·m) is set in a range from 0.1 to 8, more preferably from 1 to 6, and most preferably from 3 to 5. 
     
     
       8. A lens-fitted photo film unit as claimed in claim  5 , wherein the amount of flashlight at points which are located on an object plane above and below a photographic field, each at a vertical angle of 1.5θ relative to a center point of the photographic field, is not less than 60%, and more preferably not less than 80%, of the amount of flashlight at the center point of the photographic field, wherein θ represents a vertical angle of a top margin or a bottom margin of the photographic field relative to the center point of the photographic field. 
     
     
       9. A lens-fitted photo film unit as claimed in claim  8 , wherein the flash device has a diffusion plate on its front side for providing a wide illuminating angle of the flash device. 
     
     
       10. A lens-fitted photo film unit as claimed in claim  1 , wherein the film unit further comprises a flash device for projecting a flashlight toward a photographic subject, the film unit satisfying one of the following conditions: 
       
         
           I: 0≦{( a *) 2 +( b *) 2 }≦5.0 or  
         
       
       
         
           II: 0≦{( a *) 2 +( b *) 2 }15.0 and 0°≦Y≦100°; or  
         
       
       
         
           III: 0≦{( a *) 2 +( b *) 2 }≦15.0 and 210°≦Y≦360° 
         
       
       wherein a* and b* represent chromaticness indices in CIE 1976 L*a*b* color, and Y=0° when a*, b*=0, and Y=tan −1  (b*/a*) when a* or b* is not zero, wherein 
       
         
           0°≦tan −1  (b*/a*)≦90° when a*>0 and b*≧0  
         
       
       
         
           90°≦tan −1  (b*/a*)≦180° when a*≦0 and b*≧0  
         
       
       
         
           180°≦tan −1  (b*/a*)≦270° when a*<0 and b*≦0  
         
       
       
         
           270°≦tan −1  (b*/a*)≦360° when a*>0 and b*≦0  
         
       
       and wherein the chromaticness indices a* and b* are measured by the steps of: 
       exposing the filmstrip at a proper level to light reflected from a gray reflection plate with a reflection factor of 18% while projecting flashlight from the flash device toward the gray reflection plate;  
       exposing the filmstrip at a proper level to light reflected from the gray reflection plate while illuminating it by a fluorescent lamp of F6 type by JIS Z 8719 toward the gray reflection plate;  
       printing the image of the gray reflection plate photographed by use of the fluorescent light onto a photographic paper under such a printing condition, under which CIELAB chromaticness indices a* and b* of the gray reflection plate photographed by use of the flashlight and printed on the same photographic paper have a value zero (a*, b*=0); and  
       measuring CIELAB chromaticness indices a* and b* of the gray reflection plate printed on the photographic paper.  
     
     
       11. A lens-fitted photo film unit containing a roll of unexposed film and having photographic mechanisms including a taking lens and a shutter mechanism, and a flash device for projecting a flashlight toward a photographic subject, wherein the film unit satisfies the following conditions: 
       
         
           8.0≦log 2  ( G   2 )+log  2  (1/ T )≦12.0  
         
       
       wherein G represents a guide number (ISO100·m) of the flash device, and T represents a shutter speed T of the shutter mechanism in the unit of second. 
     
     
       12. A lens-fitted photo film unit as claimed in claim  11 , wherein the flash device has a guide number (ISO100·m) in a range from 0.1 to 8, more preferably from 1 to 6, and most preferably from 3 to 5. 
     
     
       13. A lens-fitted photo film unit as claimed in claim  11 , wherein the ISO film speed of the filmstrip is not less than 640, and more preferably not less than 1000. 
     
     
       14. A lens-fitted photo film unit as claimed in claim  11 , wherein the film unit satisfies when the film unit satisfies one of the following conditions: 
       
         
           I: 0≦{( a *) 2 +( b *) 2 }≦5.0; or  
         
       
       
         
           II: 0≦{( a *) 2 +( b *) 2 }15.0 and 0°≦Y≦100°; or  
         
       
       
         
           III: 0≦{( a *) 2 +( b *) 2 }≦15.0 and 210°≦Y≦360° 
         
       
       wherein a* and b* represent chromaticness indices in CIE 1976 L*a*b* color, and Y=0° when a*, b*=0, and Y=tan −1  (b*/a*) when a* or b* is not zero, wherein 
       
         
           0°≦tan −1  (b*/a*)≦90° when a*>0 and b*≧0  
         
       
       
         
           90°≦tan −1  (b*/a*)≦180° when a*≦0 and b*>0  
         
       
       
         
           180°≦tan −1  (b*/a*)≦270° when a*<0 and b*≦0  
         
       
       
         
           270°≦tan −1  (b*/a*)≦360° when a*>0 and b*≦0  
         
       
       and wherein the chromaticness indices a* and b* are measured by the steps of: 
       exposing the filmstrip at a proper level to light reflected from a gray reflection plate with a reflection factor of 18% while projecting flashlight from the flash device toward the gray reflection plate;  
       exposing the filmstrip at a proper level to light reflected from the gray reflection plate while illuminating it by a fluorescent lamp of F6 type by JIS Z 8719 toward the gray reflection plate;  
       printing the image of the gray reflection plate photographed by use of the fluorescent light onto a photographic paper under such a printing condition, under which CIELAB chromaticness indices a* and b* of the gray reflection plate photographed by use of the flashlight and printed on the same photographic paper have a value zero (a*=0, and b*=0); and  
       measuring CIELAB chromaticness indices a* and b* of the gray reflection plate printed on the photographic paper.  
     
     
       15. A method for making photo-prints comprising the steps of: 
       photographing picture frames on a filmstrip by a lens-fitted photo film unit with a flash device, at a shutter speed and an aperture size that satisfy the following conditions:  
       
         
           −6≦2log 2 ( A )+log 2 (1/ T )−log 2 (0.3· S )≦5  
         
       
       
         
           8.0≦log 2  ( G   2 )+log 2  (1/ T )≦12.0  
         
       
       wherein A, T, S and G represent the aperture size, the shutter speed in the unit of second, and ISO film speed of the filmstrip, and a guide number (ISO100·m) of the flash device respectively; 
       picking up image data from the picture frames;  
       processing the image data so as to virtually elongate latitudes of characteristic curves of the filmstrip in an under-exposure range; and  
       printing images on the basis of processed image data.